Got a real curly one that has me stumped...long post alert.

This just happened today and is a bit disconcerting actually.

the backstory
So today my friend who also has an ls430 went for a drive to visit his folks about an hour up the road in his ls430 this morning.

Does whatever the trip was for.

Goes to drive home again 5 hours later starts the car up is reversing out but the folding mirrors are not unfolding after start up regardless of the switch position.

So he switched the car off and went to turn it back on to give it a "reboot" but the car wouldn't start. The barrel won't turn at all.
Puts the smart key fob into the switch which turns the barrel when inserted but no starter motor... strange. Aftermarket keyfob doesn't fit into switch.
so now the car is stuck halfway in the driveway. We'll at least can move transmission into neutral with the detent button.

After multiple attempts to get the car to start, thinking it is potentially the 12v battery gets a jump battery from folks garage, but still no starter motor

starts checking other systems:
doors won't lock with the remote
doors won't lock with interior buttons or slide out key unserted in door ( drivers door physically locks, the rest don't lock with it)
headlight work, wipers work, indicators work
drivers power window works, all passenger windows stopped working (from the buttons on drivers door)
Front seats move, rears seat electrical don't
boot won't open by the dash button or remote button

So he gets a multimeter, checks the main battery. Has a solid 12.6 volts...

Disconnects battery for 10 minutes to give computer a reset, reconnects, still no start.

tries with a jump starter battery again - nothing.

At this point I get a call,
So I gathered some tools and my techstream laptop, collect his spare key. Drive up for an hour to try and help. When I get there I have a quick look over everything, nothing obvious stands out.

I hand him the spare key. (tatty but original key fob housing). Car starts up instantly first go with the spare key inserted in the switch!...

Woohoo!
At least car works and we can completely rule out low battery issues. But also at the same time wtf!

Try the original key again- nothing
revert back to the spare. Fires straight up, no hesitation at all.
remote locking still doesn't work on either key.
weird!

Connect the techstream to the car to see if there are any codes or if perhaps we can re-pair the main key
techstream connects eventually and detects some computers but is lacking usual info or utility functions in it.
techstream is slow at the best of times but this time was waay slower than normal.
No codes.....no usual info. Futile. Can't get into key pairing module.
Reboot laptop
try a second time in case. No difference

So we start pulling and checking fuses. There are a lot of them in the LS....All are perfect....

Bugger! Dead end again.
1 key works 1 doesn't (Edit: Both keys work in the actual switch.) many system's suddenly faulty, now obvious rhyme or reason why somethings work and others don't.
No easy or obvious cause or fix.

Ok. Regroup.

So at least the car is drivable using the spare key. We drive it back, mirrors folded in for the whole journey.

Now it is now back at his home in the garage where we can work on it easily.

But mirrors still won't unfold
Drivers power window works, (all others still don't from the swiches on the drivers door)
doors won't lock
instruments work
Rear seat, nothing electrical works.
Rear blind goes up and down fine
Headlights, indicators and tail lights work (thankfully)
Wipers work (also good as it has been raining a lot lately)
the spare key works to turn car on in the switch, the main key now doesn't The smart key function stopped working(the battery in key fob is now new just in case it was that)
Using techstream on the car shows no codes and few utilities.

It's a real disconcerting scenario to see your key get unpaired just like that. Imagine if that happened on a road trip somewhere... stop working like normal.

It's the end of the day now so we have disconnected the battery to let it sit over night. Hopefully whatever the thing is will reset itself magically and be back to normal tomorrow. With any luck that's all it is. Fingers crossed.

Questions:
Has anyone else suffered from or know of someone who has an ls430 or similar vintage Lexus/ Toyota that had similar sudden widespread electrical issues when battery and all fuses are good?

Any thoughts on what on earth could be causing this weird behaviour? Or better still how to fix it?

A couple of little circumstantial details may be related may be not:

-It has been raining a bit lately, no known leaks in the car that we are aware of (carpets seem dry). Do ls430s have any "usual suspect" places to check for?

The car is largely stock aside from an aftermarket stereo fitted a year ago, I doubt that would cause any of these problems more than 12 months later.

Recently fitted LED side indicator lamps. Could LED indicators cause weird and seemingly unrelated electrical problems?

My thoughts are that it has to be related to one of the computers or the communication bus in some way.
Any ideas on where to start looking next?
Body computer perhaps?
If so where is it physically located

Luckily we can take parts from my lexus and swap to see if that fixes it.

cheers

P.s. typing this on my phone in bed so forgive typos and or unspotted auto incorrects.

 

It absolutely can be the radio if the car CAN bus routes through it. Check all engine and chassis grounds

 

FWIW a battery can have a dead cell or intermittent issue that makes things go wonky. Battery may even load test OK. Best advice would be to test with a fresh battery.

 

Couple of updates:

The disconnect over night didn't changes anything
I was wrong about the ket unpaired. Turns out that key was using a housing that won't fit

 

I also think engine and/or chassis grounds may be the culprit. Corrosion, loose wire, broken wire, etc. Check them all. You may need some diagrams to help you find them.

 

That's what I would check first.

 

Thanks tomin, will check then grounds out today.

Also we are going to have a look at swapping something called a "gateway computer". It's somewhere in that dash under the windscreen.

I have a feeling that the gateway may be causing some or all of the problems as it is responsible for sending instructions between the different computer modules in the car: here is why

The symptoms are:
Ignition works with key but no smart starting function (signal from key receiver not making it to ignition switch)

no remote door locking.(signal from receiver not making it to lock controller)

mirrors won't unfold (no signal making it to mirror motor controller)

no central locking (because signals not making it from door buttons to the actuators)

boot/trunk only key barrel open ( because the signal from dash button or key receiver isn't making it to the boot/trunk release unit)

Same thing for fuel cover panel.

Drivers window works only on driver door, window on each door works with the button on each door individually, but not the remote buttons (because Jim morrison is no longer talking to other doors - Ray Manzarek, Robby Krieger, and John Densmors)

headlights work but not the auto light function (signal from light sensor not being recieved by headlight controller)

wipers work, but not autowipe (signal not making it from rain sensor to wiper controller)

Techstream having difficulty talking to the modules because the signals aren't making it through the gateway to talk to the modules.

no codes, because everything goes through the gateway.

no fuses blown because it isn't an electrical short circuit problem, it's a network communications issue.

It's just a theory at this stage and there may be more to it because it doesn't explain some things such as why the back seat electrics stopped working in the back seat buttons. Perhaps they also get routed through the gateway before actuation.

Will report back later today when we swap my gateway computer over to see and or vice versa). Luckily if it is that, those modules are cheap and plentiful.

 

Alrighty so we still haven't found the root cause of the communication issue.

But we have learned a few things along the way about how the LS430 is configured.

Learnings:

1. In the absence of the ECU's talking to each other - the mirrors default to and remain in the closed position. We've worked around this problem by winding them out by connecting them to my car, having them wind out and then leaving them unplugged in the out position. So it's manual adjustment mirror only - which works for now but obviously isn't a great long term fix.

2. Swapping the gateway computers didn't fix it. We were able to connect using techstream to the car but interestingly the cars option packs configuration move across with the computer itself. Eg My cars navigation pack was showing up but was showing as missing in his car. This potentially means the gateway computer is somehow "keyed" to each car. I can't see any obvious setting in techstream to get things reset. If anyone knows what to do here that would be appreciated. Fairly safe to now assume that the gateway computer itself is functioning and is not the cause of the communication issue.

3. We haven't found any obvious grounds or wires that are faulty or corroded. Also been through every single fuse a second time - replacing them just in case. There are so many fuses in this car. My first car had 2. My second car had about 14. There must be over 100 in the the 5 different fuse boxes.

4. Other than being annoying that the remote or smart functions aren't working, the engineers did a good job in setting most of the modules up to function well on their own ok without the smart communication capabilities - eg each doors window switch works ok in isolation. Ignition switch works like a normal switch without smartkey functions. Engine works, cruise works, aircon works, headlights work normally without the auto light sensor function. Wipers work normally without the auto wipe function. the Auto setting in fact becomes a normal intermittent wiper. It's a bit of a pain in the butt opening the fuel flap manually - through the boot/trunk using the slide out key but it works for now.

5. The only strange default fail safe set-up being the wing mirrors defaulting to the folded IN position in absense of communication with the dash switch. Surely defaulting to the out position would be a more practical fail safe..... The other weird thing that actually works is the rear blind - it works perfectly and is pretty much irrelevant to the day to day driving of a car. Any hoo....

So we have a perfectly drivable car now - just missing auto functions that work using the CANBUS.

Any ideas on how we can get CANBUS working?
Or other things to check?

Cheers

 

If the Lexus CANBUS is the same as most others out there, it will run a comms check at ignition on and if any of the important computers does not respond, then it goes into a kind of failsafe mode.
I would suspect one of the many computers has suffered a problem due to the crappy non-lead solder used.
As for which one, chances are only a GOOD Lexus specialist could tell you which.

 

Well it's solved. The car is back to normal.
everything except the faulty part is working perfectly.

Anyone want to guess the part that caused this sudden multi function miscommunication issue?

 

Was it the ECU?

 

No thankfully. The Engine's Control Unit is working perfectly - even in absence of the network communication.

Hint: It's something so insignificant to the core operation of the vehicle.

So insignificant in fact that if these symptoms affect your car out-of-the-blue, just disconnect this thing and you could either decide to replace it or not bother at all and it wouldn't matter.

 

Stumped on this one...great thread....OK tell us.

 

My wild guess is body control module on the driver door. I noticed my car doing all sorts of weird things when I had mine disconnected last weekend.

 

You are probably going to find the cause of this little debacle very hard to believe - as I did.

In the process of trying to figure out what on earth was going on, trying this, trying that etc, my mate managed to stumble across this thread from about a decade ago which was the follow up from another thread

This the sensor for the Automatic function of the Wipers...... It is the module positioned between the interior mirror and the windshield. Better yet - you can unclip it by hand without tools, or even getting out of the drivers seat.

The moment it was unplugged, all the other functions returned to functional. - smart key, locking, auto headlights, all power windows switches on drivers door, rear seat electrics, fuel tank flap.......

The wipers still work but the auto function setting just becomes regular adjustable intermittent.....

As for why these sensors fail in that way remains a mystery, but if you ever find yourself with with spread functions suddenly dissappearing potentially away from home - look at disconnecting that sensor first.